B737 NG

 Warning Systems

15.20 Warning Systems-System DescriptionIntroductionAural, tactile and visual warning signals alert the flight crew to conditions requiring action or caution in the operation of the airplane. The character of the signals varies, depending upon the degree of urgency or hazards involved. Aural, tactile, and visual signals are used singularly or in combination to simultaneously provide both warnings and information regarding the nature of the condition.Mach/airspeed warnings, landing gear warnings, takeoff configuration warnings, windshear warnings, and ground proximity warnings are discussed in this section. Cabin altitude warning is discussed in this section and in the Air Systems briefing, and autopilot and autothrottle disconnect warnings are discussed in the Automatic Flight briefing. The conditions which excite the fire warning bell are discussed in the Fire Protection briefing.Conditions which require the immediate attention of the flight crew are indicated by red warning lights located in the area of the pilots’ primary field of vision. These lights indicate engine, wheel well, cargo, or APU fires; autopilot, autothrottle disconnects; and landing gear unsafe conditions.Conditions which require the timely attention of the flight crew are indicated by amber caution lights.Blue lights inform the flight crew of electrical power availability, valve position, equipment status, and flight attendant or ground communications. Blue lights are for information and do not require immediate flight crew attention. Some system blue lights indicate a transitional state by illuminating bright as valves or components reposition, then returning to a dim blue when the required configuration is reached. Green lights indicate a fully extended configuration, e.g., landing gear and leading edge devices.Stall warning is provided by a control column shaker on each control column.Various aural signals call attention to warnings and cautions. An aural warning for airspeed limits is given by a clacker, the autopilot disconnect by a warning tone, takeoff configuration and cabin altitude by an intermittent horn, and landing gear positions by a steady horn. The fire warning by a fire warning bell. Ground proximity warnings and alerts, and windshear warnings and alerts are given by voice warnings. Generally, aurals automatically silence when the associated non–normal condition no longer exists.

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.

G

Master Fire Warning LightsTwo master FIRE WARN lights illuminate when any fire warning condition occurs. The lights remain illuminated as long as the condition exists. Pushing either master FIRE WARN light or fire warning bell cutout switch extinguishes both lights, silences the fire warning bell and resets the system for future warnings. Further information appears in the Fire Protection section.

Master Caution LightsTwo MASTER CAUTION lights illuminate when any caution occurs outside the normal field of vision of the flight crew. The lights remain illuminated as long as the caution condition exists, or until the crew resets the system. Pushing either MASTER CAUTION light extinguishes both lights and resets the master caution system for further cautions. Pushing either annunciator light panel recalls all existing fault annunciations.A single fault in certain redundant systems, or some simple faults, do not illuminate the MASTER CAUTION or system annunciator lights. These faults, however, are stored in the master caution system. Pushing the system annunciator recalls the single fault on the system annunciator panel.When the MASTER CAUTION recall is pressed, all twelve system lights should illuminate while the press-to-test feature is held. If a system annunciator light does not illuminate, refer to the dispatch deviation procedures guide (DDPG).

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System Annunciator LightsTwo system annunciator light panels are located on the glare shield. The annunciator light panels include only those systems located on the forward overhead, aft overhead, and fire control panels. If a caution condition exists, the appropriate system annunciator(s) and MASTER CAUTION lights illuminate.

System Annunciators and Related Amber Lights – Left Side

FLT CONT ELEC

LOW QUANTITY

LOW PRESSURE

FEEL DIFF PRESS

SPEED TRIM FAIL

MACH TRIM FAIL

AUTO SLAT FAIL

YAW DAMPER

STBY RUD ON

DRIVE

STANDBY PWR OFF

TRANSFER BUS OFF

SOURCE OFF

TR UNIT

BATTERY DISCHARGE

ELEC

IRS LEFT SIDEGLARESHIELD

APU

FAULT

ON DC

DC FAIL

GPS

LOW OIL PRESSURE

FAULT

OVERSPEED

FUEL OVHT/DET

LOW PRESSURE

FILTER BYPASS

ENGINE 1 OVERHEAT

ENGINE 2 OVERHEAT

APU DET INOP

FLT CONT ELECIRS APUFUEL OVHT/DET

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System Annunciators and Related Amber Lights – Right Side

[Option - 737-800/900, ICE DETECTOR, AIRSTAIR, ELT, HIGH ALTITUDE LANDING - INOP, lavatory SMOKE detector]

ANTI–ICE ENG

WINDOW OVERHEAT

PITOT HEAT

COWL ANTI–ICE

ICE DETECTOR

REVERSER

EEC ALTN MODE

ENGINE CONTROL

HYD . OVERHEAD

OVERHEAT

LOW PRESSURE

RIGHT SIDEGLARESHIELD

ELT

EQUIP COOLING– OFF

EMER EXIT LIGHTS–NOT ARMED

FLIGHT RECORDER–OFF

PASS OXY–ON

PSEU

SMOKE

DOORS AIR COND

FWD/AFT ENTRY

AIRSTAIR

EQUIP

FWD/AFT CARGO

FWD/AFT SERVICE

LEFT/RIGHT OVERWING

ZONE TEMP

DUAL BLEED

PACK

WING–BODY OVERHEAT

BLEED TRIP OFF

AUTO FAIL

OFF SCHED DESCENT

HIGH ALTITUDE LANDING - INOP

ANTI-ICE ENGHYD OVERHEAD

DOORS AIR COND

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Warning Systems

Intermittent Cabin Altitude/Configuration WarningThe takeoff configuration warning is armed when the airplane is on the ground and either or both forward thrust levers are advanced for takeoff. An intermittent warning horn sounds if:• trailing edge flaps are not in the flaps 1 through 25 takeoff range, or• trailing edge flaps are in a skew or asymetry condition, or have

uncommanded motion, or• leading edge devices are not configured for takeoff or have uncommanded

motion, or• speed brake lever is not in the DOWN position, or• ground spoiler interlock valve is open providing pressurized hydraulic

fluid to spoiler control valves, or• parking brake is set, or.• stabilizer trim not set in the takeoff range.

The warning indication is cancelled when the configuration error is corrected.The Cabin Altitude Warning Horn activates when cabin altitude exceeds 10,000 feet. An intermittent warning horn is heard. The Cabin Altitude Warning Horn may be silenced by momentarily pressing the ALT HORN CUTOUT switch on the Cabin Altitude Panel.

WARNING: The Cabin Altitude and Takeoff Configuration Warnings usethe same intermittent tone when activated.

Landing Gear Configuration WarningsVisual indications and aural warnings of landing gear position are provided by the landing gear indicator lights and landing gear warning horn.

Visual IndicationsThe landing gear indication lights are activated by signals from each gear, the LANDING GEAR lever, and the forward thrust lever position as follows:Green light illuminated – landing gear is down and locked.Red light illuminated – • landing gear is in disagreement with LANDING GEAR lever position (in

transit or unsafe).• landing gear is not down and locked (with either or both forward thrust

levers retarded to idle, and below 800 feet AGL).All lights extinguished – landing gear is up and locked with the LANDING GEAR lever UP or OFF.

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Aural IndicationsA steady warning horn is provided to alert the flight crew whenever a landing is attempted and any gear is not down and locked. The landing gear warning horn is activated by forward thrust lever and flap position as follows:Flaps up through 10 – • altitude below 800 feet RA, when either forward thrust lever set between

idle and approximately 20 degrees thrust lever angle or an engine not operating and the other thrust lever less than 34 degrees. The landing gear warning horn can be silenced (reset) with the landing gear warning HORN CUTOUT switch

• if the airplane descends below 200 feet RA, the warning horn cannot be silenced by the warning HORN CUTOUT switch.

Flaps 15 through 25 –• either forward thrust lever set below approximately 20 degrees or an

engine not running, and the other thrust lever less than 34 degrees; the landing gear warning horn cannot be silenced with the landing gear warning HORN CUTOUT switch.

Flaps greater than 25 – • regardless of forward thrust lever position; the landing gear warning horn

cannot be silenced with the landing gear warning HORN CUTOUT switch.

The warning indication is cancelled when the configuration error is corrected.

Proximity Switch Electronic Unit (PSEU)The PSEU monitors the following systems:• takeoff configuration warnings• landing configurations warnings• landing gear• air/ground sensing.

The PSEU, its sensors, and its input signals are monitored for internal faults. When designated faults are detected, a PSEU light on the aft overhead panel illuminates, and the OVERHEAD system annunciator light and MASTER CAUTION lights illuminate. The PSEU light can be reset following a maintenance BITE check or repair of the cause of the fault. The PSEU light is inhibited:• in flight• when the thrust levers are advanced toward takeoff power• for 30 seconds after landing.

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Mach/Airspeed Warning System Two independent Mach/airspeed warning systems provide a distinct aural warning, a clacker, any time the maximum operating airspeed of Vmo/Mmo is exceeded. The warning clackers can be silenced only by reducing airspeed below Vmo/Mmo. The airspeed indicator displays red warning bands indicating maximum and minimum airspeeds. Amber bands indicate maximum and minimum maneuvering airspeeds. The top of the lower amber band indicates the minimum maneuver speed. It is the slowest speed that provides full maneuvering: 0.3 g maneuver margin (40° bank) to stick shaker (below approxiametly 20,000 ft) or initial buffet (above approximately 20,000 ft).The airspeed indicator displays red warning bands indicating maximum and minimum airspeeds. Amber bands indicate maneuver capability. The top of the lower amber band indicates the minimum maneuver speed for full maneuver capability. This speed provides 0.3 g maneuver margin (40° bank) to stick shaker (below approximately 20,000 feet) or initial buffet (above approximately 20,000 feet). As airspeed is decreased below the top of the amber band, maneuver capability decreases. In 1 g flight, the speed in the middle of the amber band provides adequate capability (30° bank). The bottom of the amber band (top of the barber pole) corresponds to stick shaker or initial buffet onset speed, and increases with g loading.When either an overspeed condition or a system test occurs, the ADIRU transmits a signal to the aural warning module, sounding the clacker. The system can only be tested on the ground.

Stall Warning SystemNatural stall warning (buffet) usually occurs at a speed prior to stall. In some configurations the margin between stall and natural stall warning is less than desired. Therefore, an artificial stall warning device, a stick shaker, is used to provide the required warning.The stall warning “stick shaker” consists of two eccentric weight motors, one on each control column. They are designed to alert the pilots before a stall develops. The warning is given by vibrating both control columns. The system is armed in flight at all times. The system is deactivated on the ground.Two independent, identical stall management yaw damper (SMYD) computers determine when stall warning is required based upon:• alpha vane angle of attack outputs• ADIRU outputs• anti–ice controls• wing configurations

• air/ground sensing

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• thrust• FMC outputs.• mach compensation

The SMYD computers provide outputs for all stall warning to include stick shaker and signals to the pitch limit indicator and airspeed displays and the GPWS windshear detection and alert.Two test switches are installed in the aft overhead panel. Pushing either of these initiates a self–test of the respective stall warning channel. The No.1 activates the Captain stick shaker, and the No. 2 activates the F/O stick shaker. Either stick shaker vibrates both columns through column interconnects.

Autoland Advisory Messages[Option – Fail-Operational Autoland Capability]When a system failure is detected that affects autoland status, an advisory message is displayed on the upper engine display. Two advisories, NO LAND 3 and NO AUTOLAND, are available. Only one advisory message can be displayed at one time. A cancel/recall switch, located on the MFD panel, controls the display and recall of the advisory messages.The NO LAND 3 advisory will be annunciated when a failure has occurred above Alert Height and the system is still capable of continuing to a safe landing. With this advisory, LAND 2 will be the resulting autoland status annunciation displayed following dual autopilot engagement on approach.The NO AUTOLAND advisory is displayed any time above the Alert Height to notify the crew a failure has occurred and the system is unable to perform an automatic landing.

Altitude Alerting System[Option - EFIS/MAP, 300/900 altitude alert]Altitude alerting occurs when approaching or departing the MCP–selected altitude. Altitude alerting is inhibited when trailing edge flaps are extended to 25 or greater, or while G/S is captured.

Acquisition Alerting900 feet before reaching the selected altitude, both ALT ALERT annunciations show and a momentary tone sounds. At 300 feet from selected altitude, the ALT ALERT annunciations no longer show.

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Deviation AlertingWhen deviating by 300 feet from the selected altitude, a momentary tone sounds and the ALT ALERT annunciations flash. Flashing continues until:• altitude deviation becomes less than 300 feet• altitude deviation becomes more than 900 feet• a new altitude is selected.

Altitude Alert Profile

Altitude Alerting System[Option - PFD/ND, 300/900 altitude alert]Altitude alerting occurs when approaching or departing the MCP–selected altitude. Altitude alerting is inhibited when trailing edge flaps are extended to 25 or greater, or while G/S is captured.

and annunciations flash.

+300'

-300'

ALT ALERT

and annunciations show.

Deviation - Aural warning tone momentarily sounds

Acquisition - Aural warning tone momentarily soundsNO INDICATIONS

+900'

-900'

ALTITUDE

SEL

SELECTEDALTITUDE

ALT ALERT

CAUTION AURAL

CAUTIONAURAL

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Acquisition Alerting900 feet before reaching the selected altitude, a white box shows around the selected altitude display and the box around the current altitude becomes bold. A momentary tone sounds. At 300 feet from selected altitude, the selected altitude box no longer shows.

Deviation AlertingWhen deviating by 300 feet from the selected altitude, a momentary tone sounds and the current altitude box turns amber and begins to flash. The amber flashing continues until:• altitude deviation becomes less than 300 feet• altitude deviation becomes more than 900 feet• a new altitude is selected.

Altitude Alert Profile

+300'

-300'

Acquisition - Aural warning tone momentarily sounds.NO INDICATIONS

+900'

-900'

SELECTEDALTITUDE

CAUTION AURAL

CAUTIONAURAL

A box shows around the selected altitude display

Deviation - Aural warning tone momentarily soundsand current altitude box turns amber and flashes.

and the box around current altitude becomes bold.

ALTITUDE

SEL

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Ground Proximity Alerts The GPWS provides alerts for potentially hazardous flight conditions involving imminent impact with the ground. The GPWS monitors terrain proximity using an internal world wide terrain data base. Proximate terrain data shows on the navigation display. If there is a potential terrain conflict, alerts are provided based on estimated time to impact. These alerts are “look-ahead terrain alerts.” The GPWS provides alerts based on radio altitude and combinations of barometric altitude, airspeed, glide slope deviation, and airplane configuration. The alerts are for:• excessive descent rate• excessive terrain closure rate• altitude loss after takeoff or go-around• unsafe terrain clearance when not in the landing configuration• excessive deviation below an ILS glide slope

[Option - IAN]• excessive deviation below glidepath

These alerts are “radio altitude based alerts.”Ground proximity alerts are accompanied by voice aural alerts and the PULL UP annunciation on the attitude indicators or, for deviation below glide slope alert, the BELOW G/S light.

Note: Terrain ahead of the airplane may exceed available climb performance. A ground proximity alert does not guarantee terrain clearance.

Look-ahead terrain alerts and radio altitude based alerts are prioritized based on the level of hazard and the required flight crew reaction time. Look-ahead terrain alerts and radio altitude based alerts are inhibited by an actual windshear warning (airplane in windshear).

Look–Ahead Terrain AlertingThe GPWS terrain data base contains detailed terrain data near major airports, and data in lesser detail for areas between airports. Terrain within 2,000 feet of airplane barometric altitude shows on the navigation display. The terrain data is not designed to be an independent navigation aid.

Note: The GPWS terrain data base, look-ahead terrain alerting, and terrain display do not account for man made obstructions.

The terrain display is generated from a data base contained in the GPWS computer and correlated to GPS position.

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Terrain and weather radar cannot show together on a display. If one pilot selects terrain and the other pilot selects weather radar, each display updates on alternating sweeps. All other displays (TCAS, LNAV routing, etc.) can show with terrain data.Look-ahead terrain alerts are based on the airplane’s position, barometric altitude, vertical flight path, and ground speed.

Look Ahead Terrain Alerts

AURAL ALERT

VISUAL ALERT DESCRIPTION

TERRAIN TERRAINPULL UP

PULL UP on both attitude indicators

Red TERRAIN message on navigation display (all modes)

Solid red terrain on navigation display

20 to 30 seconds from projected impact with terrain shown solid red on the navigation display (in expanded MAP, center MAP, expanded VOR, or expanded APP modes only).

Moving the ground proximity terrain inhibit switch to TERRAIN INHIBIT inhibits the alert.

CAUTION TERRAIN

Amber TERRAIN message on navigation display (all modes)

Solid amber terrain on navigation displays

40 to 60 seconds from projected impact with terrain shown solid amber on the navigation display (in expanded MAP, center MAP, expanded VOR, or expanded APP modes only).

Moving the ground proximity terrain inhibit switch to TERRAIN INHIBIT inhibits the alert.

TOO LOW, TERRAIN

PULL UP on both attitude indicators

Descent below unsafe radio altitude while too far from any airport in the terrain database.

Moving the ground proximity terrain inhibit switch to TERRAIN INHIBIT inhibits the alert.

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Radio Altitude Based AlertsAURAL ALERT VISUAL ALERT DESCRIPTION

PULL UP PULL UP on both attitude indicators

Follows SINK RATE alert if descent rate becomes severe.

Follows radio altitude based TERRAIN alert if excessive terrain closure rate continues and landing gear and/or flaps are not in landing configuration.

TERRAIN PULL UP on both attitude indicators

Excessive terrain closure rate.

DON’T SINK PULL UP on both attitude indicators

Excessive altitude loss after takeoff or go–around.

GLIDE SLOPE BELOW G/SP–INHIBITlights

Deviation below glide slope. Volume and repetition rate increase as deviation increases.

Pushing the ground proximity BELOW G/S P-INHIBIT light cancels or inhibits the alert below 1,000 feet RA.

SINK RATE PULL UP on both attitude indicators

Excessive descent rate.

TOO LOW, FLAPS

PULL UP on both attitude indicators

Unsafe terrain clearance at low airspeed with flaps not in a normal landing position.

Pushing the ground proximity flap inhibit switch to FLAP INHIBIT inhibits the alert.

TOO LOW, GEAR

PULL UP on both attitude indicators

Unsafe terrain clearance at low airspeed with landing gear not down.

Pushing the ground proximity gear inhibit switch to GEAR INHIBIT inhibits the alert.

TOO LOW, TERRAIN

PULL UP on both attitude indicators

Unsafe terrain clearance at high airspeed with either landing gear not down or flaps not in landing position. Follows DON’T SINK if another descent is initiated after initial alert, before climbing to the altitude where the initial descent began.

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Windshear AlertsWindshear alerts are available during takeoff, approach, and landing: • The GPWS provides a warning when the airplane is in a windshear. • The weather radar provides alerts for excessive windshear ahead of the

airplane. These are “predictive windshear alerts.” Windshear warnings are accompanied by WINDSHEAR on the attitude indicators and voice aural alerts. Windshear cautions are accompanied by a voice aural alert. Windshear alerts are prioritized based on the level of hazard and the required flight crew reaction time. Predictive windshear alerts are inhibited by an actual windshear warning (airplane in windshear), look-ahead terrain alerts, or radio altitude based alerts.

Windshear Warning (Airplane in Windshear)

Predictive Windshear AlertsThe weather radar uses radar imaging to detect disturbed air prior to entering a windshear.

Note: The weather radar provides windshear alerts for windshear events containing some level of moisture or particulate matter.

Note: The weather radar detects microbursts and other windshears with similar characteristics. The weather radar does not provide alerting for all types of windshear. The flight crew must continue to rely on traditional windshear avoidance methods.

AURAL ALERT VISUAL ALERT DESCRIPTION

Two–tone siren followed by WINDSHEAR

Red WINDSHEAR on both attitude indicators.

Excessive windshear at the current airplane position detected by GPWS.

Enabled below 1,500 feet RA.

GPWS Windshear detection begins at rotation.

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The weather radar automatically begins scanning for windshear when: • thrust levers set for takeoff, even if engine is off or IRS not aligned, or• in flight below 2,300 feet RA (predictive windshear alerts are issued

below 1,200 feet RA).

[Option - Without Collins weather radar 622-5132-632 or 622-5132-633]Alerts are available approximately 12 seconds after the weather radar begins scanning for windshear. Predictive windshear alerts can be enabled prior to takeoff by pushing the EFIS control panel WXR switch.

AURAL ALERT

VISUAL ALERT DESCRIPTION

WINDSHEAR AHEAD

Red WINDSHEAR on both attitude indicators

RED windshear symbol on navigation display

Red WINDSHEAR message on navigation display (all modes)

Windshear close to and directly ahead of the airplane detected by the weather radar.

Enabled during takeoff, below 1,200 feet RA.

Predictive windshear symbol on the navigation display shows windshear position (expanded MAP, center MAP, expanded VOR or expanded APP modes only).

GO AROUND, WINDSHEAR AHEAD

Red WINDSHEAR on both attitude indicators

RED windshear symbol on navigation display

Red WINDSHEAR message on navigation display (all modes)

Windshear within 1.5 miles and directly ahead of the airplane detected by the weather radar.

Enabled during approach, below 1,200 feet RA.

Predictive windshear symbol on the navigation display shows windshear position (expanded MAP, center MAP, expanded VOR or expanded APP modes only).

MONITOR RADAR DISPLAY

RED windshear symbol on navigation display

Amber WINDSHEAR message on navigation display (all modes)

Windshear within 3 miles and ahead of the airplane detected by the weather radar.

Enabled during takeoff and approach, below 1,200 feet RA.

Predictive windshear symbol on the navigation display shows windshear position (expanded MAP, center MAP, expanded VOR or expanded APP modes only).

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[Option - With Collins weather radar 622-5132-632 or 622-5132-633]Alerts are available approximately 12 seconds after the weather radar begins scanning for windshear. Predictive windshear alerts can be enabled prior to takeoff by pushing the EFIS control panel WXR switch. When PWS is enabled, radar antenna scan sweep is reduced.If windshear is not detected, weather radar returns show only after pushing the EFIS control panel WXR switch.

Predictive Windshear InhibitsDuring takeoff and landing, new predictive windshear caution alerts are inhibited between 80 knots and 400 feet RA, and new warning alerts between 100 knots and 50 feet RA. These inhibits do not remove existing predictive windshear alerts.

Bank Angle AlertThe GPWS provides the aural alert BANK ANGLE, BANK ANGLE when roll angle exceeds 35 degrees, 40 degrees, and 45 degrees. Once sounded, the alert is silent for that bank angle (35, 40, or 45 degrees) until the system is reset by decreasing bank angle to 30 degrees or less.

.5 NM

1.5 NMWARNING

Predictive Windshear Alert Area

25°

On Ground

25°

3 NM

W

A

R

N

I

N

G

Caution Caution

25°

In Flight

25°

3 NM

Caution

.5 NM

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Approach Callouts

Radio Altitude Callouts[Option - Typical]The GPWS provides the following altitude callouts during approach:• 2,500 feet – TWENTY FIVE HUNDRED• 1,000 feet – ONE THOUSAND• 500 feet – FIVE HUNDRED• 100 feet – ONE HUNDRED• 50 feet – FIFTY• 40 feet – FORTY• 30 feet – THIRTY• 20 feet – TWENTY• 10 feet – TEN.

Note: Callouts at 1000 feet and 500 feet are based on barometric altitude above the landing field elevation; callouts at 2,500 feet, and below 500 feet are based on radio altitude.

DH/MDA CalloutsThe GPWS provides height callouts based on the altitude set by the Captain’s Minimums selector.

[Option - PFD/ND]Callouts are based on radio altitude when the MINS selector is set to RADIO. Callouts are based on barometric altitude when the MINS selector is set to BARO:• DH/MDA plus 100 feet – PLUS HUNDRED• at DH/MDA – MINIMUMS

[Option - EFIS/MAP]Callouts are based on radio altitude:• DH/MDA plus 100 feet – PLUS HUNDRED• at DH/MDA – MINIMUMS

Traffic Alert and Collision Avoidance System (TCAS)TCAS alerts the crew to possible conflicting traffic. TCAS interrogates operating transponders in other airplanes, tracks the other airplanes by analyzing the transponder replies, and predicts the flight paths and positions. TCAS provides advisory and traffic displays of the other airplanes to the flight crew. Neither advisory, guidance, nor traffic display is provided for other airplanes which do not have operating transponders. TCAS operation is independent of ground–based air traffic control.

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To provide advisories, TCAS identifies a three dimensional airspace around the airplane where a high likelihood of traffic conflict exists. The dimensions of this airspace are based upon the closure rate with conflicting traffic.TCAS equipment interrogates the transponders of other airplanes to determine their range, bearing, and altitude. A traffic advisory (TA) is generated when the other airplane is approximately 40 seconds from the point of closest approach. If the other airplane continues to close, a resolution advisory (RA) is generated when the other airplane is approximately 25 seconds from the point of closest approach. The RA provides aural warning and guidance as well as maneuver guidance to maintain or increase separation from the traffic. Non–transponder equipped airplanes are invisible to TCAS. RAs can be generated if the other airplane has a mode C transponder. Coordinated RAs require both airplanes to have TCAS.

Advisories and DisplaysTAs are indicated by the aural “TRAFFIC, TRAFFIC” which sounds once and is then reset until the next TA occurs. The TRAFFIC annunciation appears on the navigation display. The TA symbol appears at the proper range and relative bearing of the other airplane. Altitude and vertical motion are included with the symbol if the other airplane is using transponder mode S or C.RAs are indicated by one or more aural listed in the RA aural table. The TRAFFIC annunciation and RA symbol which depicts the traffic’s relative bearing, range, altitude, and vertical motion are on the navigation display similar to the TA symbol.Additional symbols are proximate traffic and other traffic. Proximate traffic is within six miles and 1200 feet vertically, but is not expected to cause a TA or RA alert. Other traffic is beyond the six mile and 1200 feet vertical criteria. Traffic symbols are revised as the TCAS system constantly reevaluates the motion of other airplanes.If the range of the navigation display does not permit the display of a TA or RA an OFFSCALE annunciation appears on the navigation display.TA or RA traffic detected by TCAS which do not provide a bearing generate a no–bearing text block beneath the TRAFFIC text on the navigation display. The text block contains distance, altitude, and vertical motion information.Vertical motion information is indicated by an arrow depicting a climb or descent if a change of greater than 500 feet per minute is detected.

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TCAS display automatically shows when:• the transponder mode selector is in TA ONLY or TA/RA, and• a TCAS TA or RA occurs, and• neither pilot has the TCAS (TFC) display selected, and• in MAP, center MAP, VOR, or APP modes.

Inhibits[Option - With TCAS change 7.0 update]INCREASE DESCENT RAs are inhibited below approximately 1,500 feet radio altitude.DESCEND RAs are inhibited below approximately 1,100 feet radio altitude.RAs are inhibited below approximately 1,000 feet radio altitude. Below 1,000 feet when the TA/RA mode is selected on the transponder panel, TA only mode is enabled automatically and the TCAS message TA ONLY displays on the ND.All TCAS voice annunciations are inhibited below approximately 500 feet radio altitude.All TCAS alerts are inhibited by GPWS and windshear warnings.

Mode ControlThe TCAS operating mode is controlled from the TCAS/ATC transponder panel. TCAS is normally operated in the TA/RA mode. However, sometimes it is necessary to operate in the TA ONLY mode to prevent undesired RAs. For example, TA ONLY may be selected when intentionally operating near other airplanes such as might be found in VFR conditions at a busy airport, or on parallel approach.ATC transponders on TCAS equipped airplanes communicate to provide appropriate coordinated avoidance maneuvers. When performance is limited, such as with an inoperative engine, select TA ONLY to prevent receiving RAs beyond the airplane’s capabilities, and to prevent communicating to other airplanes an ability to perform a RA maneuver.

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Resolution Advisory AuralsThe following table identifies the possible callouts associated with RAs and the vertical restrictions or maneuver recommended in each case.

[Option - With TCAS change 7.0 update]AURAL ALERTS VERTICAL

RESTRICTIONS/MANEUVER

MONITOR VERTICAL SPEED Present pitch attitude is outside the RA pitch command area. Keep pitch attitude away from red area.MAINTAIN VERTICAL SPEED,

MAINTAIN

MAINTAIN VERTICAL SPEED, CROSSING MAINTAIN

CLIMB, CLIMB Climb at the displayed pitch

DESCEND, DESCEND Descend at the displayed pitch

ADJUST VERTICAL SPEED,

ADJUST

Reduce climb or descent rate

CLIMB, CROSSING CLIMB,

CLIMB, CROSSING CLIMB

Climb at displayed pitch. Airplane climbs through traffic’s altitude.

DESCEND, CROSSING DESCEND

DESCEND, CROSSING DESCEND

Descend at displayed pitch. Airplane descends through traffic’s altitude.

INCREASE CLIMB,

INCREASE CLIMB

Increase climb rate from initial pitch attitude.

INCREASE DESCENT,

INCREASE DESCENT

Increase descent rate from initial pitch attitude.

CLIMB – CLIMB NOW,

CLIMB – CLIMB NOW

Reversal maneuver from initial descent RA.

DESCEND – DESCEND NOW,

DESCEND – DESCEND NOW

Reversal maneuver from initial climb RA.

CLEAR OF CONFLICT RA encounter terminated. Maneuver guidance no longer displayed.

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Tail Skid[737-800/-900]The tail skid assembly consists of a cartridge assembly, tail skid, fairing (skirt) and shoe. The fairing provides an enclosure for the actual tail skid structure. The shoe is fitted to the bottom of the fairing.The cartridge assembly consists of a crushable honeycomb material. When the tail skid strikes the runway the skid moves upward and the honeycomb material crushes. The tail skid is serviceable when the cartridge warning decal shows both green and red. The green disappears gradually as the cartridge is crushed. When the warning decal is all red, the cartridge must be replaced.The shoe is what contacts the runway in the event of an over rotation. The shoe surface displays “wear dimples” which serve as a reference for shoe replacement.

Tail Skid Detail

SKIRT

FAIRINGSHOE

REAR OF SKIRT(LOOKING FWD)

FAIRINGSKIRT

CRUSHED

WEAR DIMPLESSHOE

VISIBLE GREEN INDICATES

NEW CARTRIDGEREAR OF SKIRT(LOOKING FWD)

REPLACE CARTRIDGE

WARNING DECAL

FULL RED INDICATES CARTRIDGE

CARTRIDGE

CARTRIDGE IS USABLE. .NEEDS TO BE REPLACED.

SHOEWEAR

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15.10 Warning Systems-Controls and IndicatorsFire Warning and Master Caution System

1 Master Fire Warning (FIRE WARN) LightsIlluminated (red) – indicates a fire warning (or system test) in engine, cargo, APU or main gear wheel well• fire warning bell sounds• if on ground, remote APU fire warning horn sounds.

Push –• extinguishes both master FIRE WARN lights• silences fire warning bell• silences remote APU fire warning horn• resets system for additional warnings.

Note: Pushing fire warning bell cutout switch on overheat/fire protection panel results in same actions.

2 MASTER CAUTION LightsIlluminated (amber) – a system annunciator light has illuminated.Push – extinguishes both MASTER CAUTION lights• system annunciator light(s) extinguish• resets system for additional master caution conditions.

RIGHT SIDE

LEFT SIDE

AIR COND

OVERHEAD

ENG

DOORS

HYD

ANTI-ICE

ELEC

APU

OVHT/DETFUEL

IRS

FLT CONT

BELL CUTOUT

WARNFIRE MASTER

CAUTIONPUSH TO RESET

MASTERCAUTIONPUSH TO RESET BELL CUTOUT

WARNFIRE

1

2

3

GLARESHIELD

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3 System Annunciator PanelIlluminated (amber) – an amber light, relating to illuminated system annunciator, has illuminated on forward overhead, aft overhead or overheat/fire protection panel.To extinguish – push either MASTER CAUTION light.To recall – push and release either system annunciator panel• if a master caution condition exists, appropriate system annunciator(s)

and MASTER CAUTION lights illuminate• a single fault in certain redundant systems, or some simple faults, cause

the system annunciator light to illuminate during a recall. The system annunciator light will extinguish when the MASTER CAUTION light is pushed.

Proximity Switch Electronic Unit Light

1 Proximity Switch Electronic Unit (PSEU) LightIlluminated (amber) – • on the ground –

• a fault is detected in the PSEU, or• an overwing exit flight lock fails to disengage when commanded.

• in-flight –• inhibited from thrust lever advance for takeoff until 30 seconds after

landing.

Supplemental Proximity Switch Electronic Unit Light

PSEU1

AFT OVERHEAD

SPSEU1

AFT OVERHEAD

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1 Supplemental Proximity Switch Electronic Unit (SPSEU) LightIlluminated (amber) – a mid-exit flight lock fails to respond when commanded.

Takeoff Configuration and Cabin Altitude Warning Lights

1 Takeoff Configuration Warning LightIlluminated (red) –• activates on the ground as the throttles are advanced if the airplane is not

configured correctly for takeoff• activation is simultaneous with aural warning intermittent horn for

TAKEOFF CONFIGURATION alert.

2 Cabin Altitude Warning LightIlluminated (red) –• illuminates at 10,000 feet if the cabin has not been pressurized• illuminates during flight when loss of cabin pressure occurs• activation is simultaneous with aural warning intermittent horn for

CABIN ALTITUDE alert.

LEFT FORWARD PANEL

RIGHT FORWARD PANEL

TAKEOFFCONFIG

CABINALTITUDE1 2

TAKEOFFCONFIG

CABINALTITUDE

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Autoland Advisory Message Display[Option – Fail-Operational Autoland Capability]

1 MFD Cancel/Recall (C/R) SwitchPush (once) – Cancels autoland advisory messages.Push (again) – Recalls autoland advisory messages.

2 Autoland Advisory MessageAn amber autoland advisory message appears on the upper engine display when a system fault affects autoland status. Two advisories are available:• NO LAND 3 – the system is still capable of continuing to a safe landing.

A system failure has occurred above Alert Height, and a green LAND 2 status annunciation appears on the Capt and F/O outboard display unit.

• NO AUTOLAND – the system is not capable of performing an automatic landing. A system failure has occurred above Alert Height, and an amber NO AUTOLAND status annunciation appears on the Capt and F/O outboard display unit.

NO LAND 3

ENG 2ENG 1

MFD

ENG SYS

C/R

CENTER FORWARD PANEL

UPPER DISPLAY UNIT

1

2

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Mach/Airspeed Warning and Stall Warning Test Switches

1 MACH AIRSPEED WARNING TEST SwitchesPush – tests respective mach/airspeed warning system• clacker sounds• inhibited while airborne.

2 STALL WARNING TEST SwitchesPush – on ground with AC power available: each test switch tests its respective stall management yaw damper (SMYD) computer. No.1 SMYD computer shakes Captain’s control column, No.2 SMYD computer shakes First Officer’s control column. Vibrations can be felt on both columns• inhibited while airborne.

NO. 2NO. 1

STALL WARNING TEST

NO 2NO 1

AIRSPEEDWARNING

MACH

TEST

AFT OVERHEAD PANEL

1

2

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Landing Gear Warning Cutout Switch

1 Landing Gear Warning Cutout SwitchPush – silences landing gear configuration warning aural indication at flaps up through 10 and above 200 feet RA.

Note: The aural indication cannot be silenced with the cutout switch at flaps greater than 10.

Altitude Alert[Option - EFIS/MAP]

1 Altitude Alert (ALT ALERT) Annunciation

[Option - 300/900 Altitude alert]One on each pilot’s primary display above altimeter.

HORNCUTOUT

15

25

30

40

DOWNFLAP

APLNOSEUP

10

15

CONTROL STAND

1

ALT ALERT

ABOVE EACH PILOT’SALTIMETER

1

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Page 27

Displayed (amber):• steady – acquisition alert:

• 900 feet from MCP selected altitude• momentary tone also sounds• 300 feet from MCP selected altitude, ALT ALERT annunciation no

longer shows.• flashing – deviation alert:

• deviation more than 300 feet from MCP selected altitude• momentary tone also sounds• flashing continues until:

• altitude deviation less than 300 feet, or• altitude deviation more than 900 feet, or• new MCP altitude selected.

[Option - PFD/ND]

1 Selected Altitude Alert

[Option - 300/900 Altitude alert]A white box shows around the selected altitude display between 900 feet and 300 feet before reaching the selected altitude.

8004

0005

5200

1005

CAPTAIN’S PFDFIRST OFFICER’S PFD

1

2

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Page 28

2 Current Altitude Alert

[Option - 300/900 Altitude alert]The white box around the current altitude display becomes bold between 900 feet and 300 feet before reaching the selected altitude.The box turns amber and flashes for 300 feet to 900 feet deviation from the selected altitude.

Ground Proximity Warning System (GPWS)

GPWS Controls[Option - With gear inhibit switch]

1 BELOW Glide Slope (G/S) lightIlluminated (amber) – below glide slope alert is active.Push – inhibits ground proximity GLIDE SLOPE alert when below 1,000 feet radio altitude.

2 Inoperative (INOP) lightIlluminated (amber) – GPWS computer malfunction or power loss• invalid inputs are being received from radio altimeter, ADIRU, ILS

receiver, IRS, FMC, stall management computers, or EFIS control panel.

BELOW G/SP-INHIBIT

TERRINHIBIT

GEARINHIBIT

FLAPINHIBIT

NORMNORMNORM

SYS TEST

GROUND PROXIMITY

INOP

LEFT AND RIGHTFORWARD PANELS

1

2

3

4 6

5

RIGHT FORWARD PANEL

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Page 29

3 Ground Proximity System Test (SYS TEST) SwitchPush –• momentarily on ground:

• BELOW G/S and GPWS INOP lights illuminate• TERR FAIL and TERR TEST show on navigation displays• PULL UP and WINDSHEAR alerts illuminate• GLIDE SLOPE, PULL UP, and WINDSHEAR aurals sound• terrain display test pattern shows on navigation displays• CAUTION TERRAIN aural sounds and TERRAIN caution message

shows on navigation displays.• until self-test aurals begin, on ground, above indications always occur

first, followed by these additional aurals:• radio altitude based alerts• bank angle alert• approach callouts• windshear alert• look ahead terrain alerts

• system test inhibited in-flight.

4 Ground Proximity FLAP INHIBIT SwitchFLAP INHIBIT – inhibits ground proximity TOO LOW FLAPS alert.NORM (guarded position) – Normal TOO LOW FLAPS alert active.

5 Ground Proximity GEAR INHIBIT Switch

[Option - With gear inhibit switch]GEAR INHIBIT – inhibits ground proximity TOO LOW GEAR alert.NORM (guarded position) – Normal TOO LOW GEAR alert active.

6 Ground Proximity Terrain Inhibit (TERR INHIBIT) Switch TERR INHIBIT – inhibits look–ahead terrain alerts and terrain display.NORM (guarded position) – Normal terrain alerts and terrain display active.

GPWS Terrain Display Select Switch

TERRPOSDATAARPTWPTSTAWXR

EFIS CONTROL PANEL

1

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Page 30

1 Terrain (TERR) Display Select Switch Push –• shows terrain data in expanded MAP, center MAP, expanded VOR, and

expanded APP modes• arms terrain data in PLN, center VOR, and center APP modes• deselects weather radar display regardless of mode selector position• second push deselects terrain display.

Terrain Display[Option - PFD/ND]

1 Terrain DisplayColor and density vary based on terrain height vs. airplane altitude:• dotted green: terrain from 2,000 feet below to 500 feet (250 feet with gear

down) below the airplane’s current altitude• dotted amber: terrain 500 feet (250 feet with gear down) below to 2,000

feet above the airplane’s current altitude • dotted red: terrain more than 2,000 feet above airplane’s current altitude • dotted magenta: no terrain data available• solid amber: look–ahead terrain caution active• solid red: look–ahead terrain warning active.

Note: In areas without terrain data, look-ahead terrain alerting and display functions not available. Radio altitude based terrain alerts function normally.

Note: Terrain more than 2,000 feet below airplane altitude or within 400 feet of nearest airport runway elevation does not show.

5

TERRAIN

GRH

TERR

NAVIGATION DISPLAY

1

2

3

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Page 31

Automatically shows when:• a look–ahead terrain alert occurs, and• neither pilot has the terrain display selected, and • in expanded MAP, center MAP, expanded VOR, or expanded APP modes.

Updates with a display sweep, similar to weather radar display.

2 Terrain Mode AnnunciationTERR (cyan) – Terrain display enabled (manual or automatic display).

3 TERRAIN AnnunciationTERRAIN (amber) – look–ahead terrain caution alert active.TERRAIN (red) – look–ahead terrain warning alert active.Shows in all navigation display modes.

Terrain Display[Option - EFIS/MAP]

TERRAIN

TERR

GRH

5

NAVIGATION DISPLAY

1

2

3

Boeing B737 NG - Systems Summary [Warning Systems]

Page 32

1 Terrain DisplayColor and density vary based on terrain height vs. airplane altitude:• dotted green: terrain from 2,000 feet below to 500 feet (250 feet with gear

down) below the airplane’s current altitude• dotted amber: terrain 500 feet (250 feet with gear down) below to 2,000

feet above the airplane’s current altitude • dotted red: terrain more than 2,000 feet above airplane’s current altitude • dotted magenta: no terrain data available• solid amber: look–ahead terrain caution active• solid red: look–ahead terrain warning active.

Note: In areas without terrain data, look-ahead terrain alerting and display functions not available. Radio altitude based terrain alerts function normally.

Note: Terrain more than 2,000 feet below airplane altitude or within 400 feet of nearest airport runway elevation does not show.

Automatically shows when:• a look–ahead terrain alert occurs, and• neither pilot has the terrain display selected, and • in expanded MAP, center MAP, expanded VOR, or expanded APP modes.

Updates with a display sweep, similar to weather radar display.

2 Terrain Mode AnnunciationTERR (cyan) – Terrain display enabled (manual or automatic display).

3 TERRAIN AnnunciationTERRAIN (amber) – look–ahead terrain caution alert active.TERRAIN (red) – look–ahead terrain warning alert active.Shows in all navigation display modes.

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Page 33

Predictive Windshear Display and Annunciations[Option - PFD/ND]

1 Predictive Windshear SymbolDisplayed (red and black) – Predictive windshear alert active.Shows windshear location and approximate geometric size (width and depth).Symbol, radials, and weather radar returns automatically show when:• predictive windshear alert occurs, and• neither pilot has WXR display selected, and • in expanded MAP, center MAP, VOR, or APP modes.

When terrain display is active, weather radar display replaces terrain display.

2 Predictive Windshear Symbol RadialsDisplayed (amber) – Predictive windshear alert active.Extend from predictive windshear symbol to help identify location of windshear event

3 WINDSHEAR Annunciation WINDSHEAR (amber) – predictive windshear caution active.WINDSHEAR (red) – predictive windshear warning active.Shows in all navigation display modes.

513R

12 15

9

WINDSHEAR

1

NAVIGATION DISPLAY

2

3

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Page 34

Predictive Windshear Display and Annunciations[Option - EFIS/MAP]

1 Predictive Windshear SymbolDisplayed (red and black) – Predictive windshear alert active.Shows windshear location and approximate geometric size (width and depth).Symbol, radials, and weather radar returns automatically show when:• predictive windshear alert occurs, and• neither pilot has WXR display selected, and • in expanded MAP, center MAP, VOR, or APP modes.

When terrain display is active, weather radar display replaces terrain display.

2 Predictive Windshear Symbol RadialsDisplayed (amber) – Predictive windshear alert active.Extend from predictive windshear symbol to help identify location of windshear event.

55

13RWINDSHEAR

GRH1

NAVIGATION DISPLAY

2

3

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Page 35

Extend from predictive windshear symbol to help identify location of windshear e

3 WINDSHEAR Annunciation WINDSHEAR (amber) – predictive windshear caution active.WINDSHEAR (red) – predictive windshear warning active.Shows in all navigation display modes.

TCAS Controls (Transponder Panel)[Option - AlliedSignal 071-01503-2601 Transponder Panel]

[Option - Gables G6992-02 Transponder Panel]

1 Transponder Mode SelectorTA (traffic advisory) – enables the display of traffic advisory (TA) targets.TA/RA (resolution advisory) – enables the display of traffic advisory (TA) and resolution advisory (RA) targets.

2

1

ALT1

2

ATCIDENT

ATC

ATC

FAIL

ATC1TA/RATA

TESTSTBY

ALT ONALT OFF

AFT ELECTRONIC PANEL

1

2

ALT SOURCE

IDENT

FAIL

ATC 12

ATC

XPNDR XPNDRTA ONLY

ALT RPTGOFFSTBY

1

1

XPNDR TA/RA

T

S

CA

TEST

AFT ELECTRONIC PANEL

1

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Page 36

Predictive Windshear Display and Annunciations[Option - EFIS/MAP]

1 Predictive Windshear SymbolDisplayed (red and black) – Predictive windshear alert active.Shows windshear location and approximate geometric size (width and depth).Symbol, radials, and weather radar returns automatically show when:• predictive windshear alert occurs, and• neither pilot has WXR display selected, and • in expanded MAP, center MAP, VOR, or APP modes.

When terrain display is active, weather radar display replaces terrain display.

2 Predictive Windshear Symbol RadialsDisplayed (amber) – Predictive windshear alert active.

55

13RWINDSHEAR

GRH1

NAVIGATION DISPLAY

2

3

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